Dual outlet burner and method

ABSTRACT

A burner includes a casing that encloses an outer plenum, the casing forming a fuel inlet and an outer nozzle at its end. An inner tube extends generally concentrically through the outer plenum and forms an inner plenum such that the casing encloses the outer plenum and the inner plenum. The inner tube forms an inner nozzle at its end. The inner nozzle is disposed generally concentrically with respect to the outer nozzle. A valve arrangement adjusts a fuel velocity separately through each of the outer nozzle and the inner nozzle to shape a flame created when the fuel is provided in an oxidant rich environment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims the benefit of U.S. Provisional PatentApplication No. 62/037,708, filed Aug. 15, 2014, which is incorporatedherein in its entirety by this reference.

BACKGROUND

Industrial furnaces, such as regenerative glass melting furnaces,operate at high temperatures, typically in the range of about 2400-3000°F., to promote furnace and process thermal efficiency. As a result,furnace and flame temperatures tend to be high, resulting in thegeneration of significant amounts of NOx emissions.

Efforts to control NOx emissions have resulted in the development ofvarious NOx control technologies. Such technologies inhibit NOxformation by modifying flame stoichiometry and the overall combustionprocess. Exemplary NOx control technologies include oxygen-enriched airstaging, in which oxygen-enriched air is introduced in stages into thecombustion process, exhaust gas recirculation, in which exhaust gas isintroduced into the primary combustion zone to reduce the flametemperature, fuel staging, in which the fuel is introduced in stagesinto the combustion process, and other methods such as oscillating andpulsed combustion. Although some of these controls have been partiallyeffective at controlling NOx emissions, they may not sufficientlyaddress NOx formation and reduction at the burner.

BRIEF SUMMARY OF THE DISCLOSURE

The present disclosure relates to a burner having a single fuel inletand inner and outer nozzle gas jet outlets, the gas velocity of theoutlets being separately controlled using two valves. In one embodiment,a first valve, which is referred to herein as a flow adjustment valve(FAV), controls gas flow and gas velocity provided to an inner nozzle ofthe burner. Operation of the FAV permits the selective increase ordecrease of a gas jet velocity leaving the inner nozzle. A second valve,which is referred to herein as the area adjustment valve (AAV), controlsgas flow and gas velocity provided through an outer nozzle of theburner. Operation of the AAV permits the selective increase or decreaseof a gas jet velocity leaving the outer nozzle. In one embodiment, aswirling device is provided to impart a swirl to the outer gas jet toswirl, which widens a flame shape. The terms “gas” and/or “gaseous fuel”as used herein refers to a flow of fuel in gas form such as natural gas,liquid petroleum gas (LPG), and other gaseous fuels commonly used inindustrial process burners to produce a flame when burned in thepresence of air and/or another oxidant. In the illustrated embodiments,the FAV and AAV allow the separate control of the inner and outer nozzlevelocity to produce a selectively adjustable flame shape that reducesNOx emissions and increases efficiency over traditional gas burners.

In one aspect, the present disclosure relates to a single fuel inlet gasburner for use in industrial regenerative glass melting furnaces andother applications. The gas burner is arranged and configured to producea separately—controlled twin jet nozzle within the burner, which changesgas jet velocity of inner and outer concentric nozzles to adjust theflame shape. In this way, the flame shape can be adjusted to lower NOx,increase efficiency and/or focus heat transfer to particular areas ofthe process. In one embodiment, an intermediate tube that is moveablewithin the burner forms the FAV to control the velocity of the innerfuel jet. As the FAV moves forward into the burner, the velocity of theinner nozzle jet is increased by the closing of a forward valve elementand the corresponding opening of a rear valve element in the burnerbody. Similarly, as the FAV moves back within the burner body, thevelocity of the inner nozzle is decreased by the closing of the rearvalve element and the corresponding opening of the forward valve elementin the burner body.

In one described embodiment, the outer gas velocity jet is controlled bythe AAV, which controls the velocity of the remaining fuel in theburner, i.e., a portion of the gas provided to the burner that does notexit the burner through the inner nozzle. As the AAV moves forward inthe burner body, the outer velocity of the outer jet is increased byreduction of the area between the inner and outer nozzle. Similarly, asthe AAV moves back in the burner body, the outer velocity of the outerjet is decreased by increasing the area between the inner and outernozzle. In alternative embodiments, more than one style of inner nozzlecan be used to fine tune the area adjustment of the AAV.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an outline view of a gas burner, from a top perspective, inaccordance with the disclosure.

FIGS. 2-5 are sectional views of the gas burner of FIG. 1 in variousoperating positions.

FIG. 6 is a sectional view of an alternative embodiment of a gas burnerin accordance with the disclosure.

Before the embodiments of the burner and method are explained in detail,it is to be understood that the invention is not limited in itsapplication to the details of construction and/or the arrangements ofthe components set forth in the following description or illustrated inthe drawings. Rather, the invention is capable of other embodiments andof being practiced or carried out in various ways. Also, it is to beunderstood that the phraseology and terminology used herein are forpurposes of description only and should not be regarded as limiting. Theuse of “including,” “comprising,” and variations thereof is meant toencompass the items listed thereafter and equivalents, as well asadditional items and equivalents thereof.

DETAILED DESCRIPTION

Reference will now be made to the drawings wherein like elements aredesignated by like reference numbers in the various views. FIG. 1illustrates an outline view of a burner 100 from a top perspective, andFIGS. 2-5 illustrate fragmentary views of the burner 100 in variousoperating positions. As shown in these illustrations, the burner 100includes a generally hollow tubular casing or outer tube 102, whichencloses an inner plenum 104 and an outer plenum 106 (FIG. 2). The outertube 102 forms an opening 108 that constitutes a main fuel inletopening. Fuel, for example, a gaseous fuel, is provided through aconduit 110 having an opening 112 in fluid communication with a fuelsource. The outer plenum 106 forms an outer nozzle opening 117 at anend. The outer nozzle opening 117 in the illustrated embodiment iswithin a converging nozzle end-piece 115 and surrounds an inner nozzleopening 118.

In the illustrated embodiment, an inner tube 114 extends generallyconcentrically through the outer tube 102 to form the inner plenum 104within the inner tube 114. An outer plenum 106 is formed in a radial gapbetween the inner tube 114 and the inner portion of the outer tube 102.In one end thereof, the inner tube 114 is open to form an inlet 116,which can provide cooling air when the burner is not operating and whichis typically plugged or otherwise blocked during burner operation. At anend opposite the inlet 116, the inner tube 114 forms the inner nozzleopening 118.

An intermediate tube 120 is disposed around the inner tube 114 and atleast partially extends within the outer tube 102. A first sealedbushing 122 extends generally radially between the outer tube 102 andthe intermediate tube 120 to fluidly block a radial gap therebetweenwhile also permitting sealable sliding displacement between the outertube 102 and the intermediate tube 120. Similarly, a second sealed, endbushing 162 extends generally radially between the intermediate tube 120and the inner tube 114 to fluid block a radial gap therebetween whilealso permitting sealable sliding displacement between the intermediatetube 120 and the inner tube 114. In the illustrated embodiment, each ofthe first and second sealed bushings 122 and 124 includes acorresponding radial seal disposed within a corresponding channel formedin the respective bushing that slidably but sealably engages the outerportion of each respective tube. During operation, each of the innertube 114 and intermediate tube 120 can move with respect to the otherand also with respect to the outer tube 102.

Along its length, the inner tube 114 forms a series of openings or fuelinlet slots 126, which in the illustrated embodiment are axially alignedat a first longitudinal segment, A, along a centerline 128 of the burner100. When the inner tube 114 moves relative to the intermediate tube 120and/or the outer tube 102, the first longitudinal segment A along thecenterline 128 of the burner 100 may also move. The intermediate tube120, which defines an intermediate plenum 129 between the inner tube 114and the outer tube 102, forms a series of openings or fuel passages oropenings 130, which are axially aligned at a second longitudinalsegment, B, along the centerline 128 of the burner 100. As with theinner tube 114, motion or translation of the intermediate tube 120relative to the outer tube 102 will also move the second longitudinalsegment B along the centerline 128 of the burner 100.

During operation of the burner 100, fuel from the fuel inlet 108 isprovided to the outer plenum 106. From the outer plenum 106, dependingon the position of the slots 126 and the openings 130, fuel may beprovided to the intermediate plenum 129 through the openings 130. Fromthe intermediate plenum 129, fuel passes through the slots 126 to theinner plenum 104. The flow area through the openings 130 can be adjustedby appropriate alignment of the openings 130 with an outer valve seat132 formed as a portion of the second sealed bushing 122 in theembodiment shown in FIG. 2. In this way, an axial position of theintermediate tube 120 can operate to open or block a flow area of theopenings 130 with respect to the valve seat 132, which will in turn havethe effect of metering the amount of fuel passing from the outer plenum106 to the inner plenum 104. Two different positions of the intermediatetube 120 are shown in the cross-sections of FIGS. 3 and 4, in which theopenings 130 transition from a fully open position (FIG. 3) to apartially closed position (FIG. 4). A fully closed position is not shownin these illustrations, but would involve the complete blocking of theopenings 130 by the valve seat 132 as the intermediate tube 120 moveseven further towards the valve seat 132 (i.e., towards the left, in theorientation shown in FIG. 4).

In the illustrated embodiment, to create a pressure in the gas, whichforces the gas to pass into the inner plenum 104, a flow area adjustmentfor fuel passing through the outer plenum 106 is provided by anarea-adjustment valve arrangement between the intermediate tube 120 andthe outer tube 102. More specifically, a frusto-conical valve element134 is connected at an end of the intermediate tube 120 that is disposedwithin the outer tube 102 and is arranged to move with the intermediatetube 120 in unison as the intermediate tube 120 slides relative to theinner tube 114. A valve seat 136 is formed on a collar or bushing 138that is integrated with the outer tube 102. A resulting annular flowarea 140 between the valve seat 136 and the bushing 138, which isadjustable, acts as a flow adjustment valve (FAV) 142 to control the gasvelocity through the inner tube 114. In other words, during operation, arestriction of gas flow through the openings 130 and the FAV 142 willcause an increased gas flow through the outer plenum 106. Similarly, anincreased flow area and gas flow through the openings 130, coupled witha reduced flow area at the FAV 142 as the intermediate tube 120 movestowards the right in the illustrations, will cause an increased pressureand flow area for gas to enter the inner tube 114, thus increasing gasflow through the inner nozzle 118. Assuming a constant gas flow providedto the burner 100, an increase in the gas flow through the inner nozzle118 will cause a corresponding decrease in the gas flow passing throughthe outer nozzle 117. The converse is also true. That is, a decrease inthe flow of gas through the inner nozzle 118 will cause a correspondingincrease in the gas flow through the outer nozzle 117 as theintermediate tube 120 moves towards the left in the illustrations.Additional flow effects may be exploited. For example, as shown in FIG.5, certain openings 130 may be configured to be proximate to the fuelinlet opening 108 in the outer tube 102 when the intermediate tube 120is sufficiently pushed forward, thus further increasing flow through theinner nozzle 118.

The burner 100 further includes a second velocity adjustment mechanismthat controls gas velocity within the outer plenum 106. In theillustrated embodiment, a contoured valve element 144 operates as anarea adjustment valve (AAV) 146, which operates to adjust an outlet flowarea for the outer nozzle opening 117. The contoured valve element 144forms a bore having an inner surface 148 that is aligned with and formspart of the inner plenum 104. The contoured valve element 144 isconnected at an end of the inner tube 114 and is disposed within theconverging nozzle end-piece 115. During operation, the contoured valveelement 144 cooperates with a contoured inner surface 146 of theconverging nozzle end-piece 115 to create, based on the position of theinner tube 114 relative to the outer tube 102, an adjustable flow areafor the outer nozzle opening 117. In the embodiment shown in FIG. 2, forexample, the flow area between the contoured valve element 144 and theinner surface 148 of the converging nozzle end-piece 115 is set to besmall, which will result in an acceleration of the gas passing throughthe outer nozzle opening 117. Correspondingly, an operating position forin the second nozzle opening 117 formed between a retracted, contouredvalve element 144 and the inner surface 148 of the converging nozzleend-piece 155, which forms a larger flow area and, thus, a lowervelocity flow through the second nozzle opening 117, is shown in FIGS. 2and 3.

On the basis of the foregoing, it can be seen that two separate valvemechanisms can be adjusted to control operation of the burner 100. Afirst valve mechanism, which is formed by the structures associated withthe FAV 142, controls the portion of gas input to the burner 100 betweenthe inner and outer nozzle openings 118 and 117. A second valvemechanism, which is formed by the structures associated with the AAV146, controls the velocity of the gas exiting through the outer nozzleopening 117. In this way, the velocity of gas exiting the inner nozzleopening 118 and outer nozzle opening 117 is controlled by two separatevalves.

In the embodiment shown, a threaded rod with a corresponding handle canbe used to manually adjust each of the FAV 142 and AAV 146, but otheractivation mechanisms and/or automatic rather than manual activationmechanisms can be used. As shown in the exemplary embodiment of FIG. 1,a first knob 150 acting on a threaded rod 152 may be threadably engagedwith a first activation arm 154 that is connected to the second sealedbushing 124. In this way, turning of the first knob 150 may cause thesecond sealed bushing 124, and thus the intermediate tube 120, to moverelative to the first sealed bushing 122 and thus the outer tube 102 tocause an adjustment of the FAV 142 as described above.

Similar to the FAV 142, activation of the AAV 146 can be carried out inthe illustrated, exemplary embodiment by a second knob 156 acting on athreaded rod 158. The threaded rod 158 is threadably engaged with asecond activation arm 160 that is connected to the end bushing 162. Theend bushing 162 is attached to an end of the inner tube 114. In thisarrangement, turning of the second knob 156 will cause the end bushing162 and inner tube 114 to move relative to the first sealed bushing 122and thus the outer tube 102 to cause an adjustment of the AAV 146 asdescribed above. In general, independent motion of each of the innertube 114 and intermediate tube 120 with respect to the outer tube 102will cause, respectively, separate adjustment of the FAV 142 and AAV146.

An alternative embodiment for a burner 200 is shown in FIG. 6. In thisembodiment, structures and features that are the same or similar tocorresponding structures and features of the burner 100 are denoted bythe same reference numerals as previously used, for simplicity. In theburner 200, which is shown in fragmentary view from the same perspectiveas the previous views of the burner 100, a swirling device 202 has beenadded to the outer plenum 106. Moreover, a contoured valve element 244having a more slender outline than the contoured valve element 144 isused to achieve an overall decrease in flow velocity through the outernozzle opening 217 of the burner 200 when compared to the flow throughthe outer nozzle opening 117 in the burner 100. As shown, the converginginner surface 248 of the end-piece 215 of the burner 200 has a more openshape allowing for a larger cross sectional flow area therein whencompared to the inner surface 148 of the converging nozzle end-piece 115of the burner 100.

The swirling device 202, which is shown in cross-section in FIG. 6, ismade from a collar 204 that fits around the inner tube 114. Helicalwalls 206 extend radially outwardly from the collar 204 and bridge thegap of the outer plenum 106 between the inner tube 114 and the outertube 102 adjacent an end of the inner tube 114 that is close to theinner nozzle opening 118. The walls 206 have a generally helical shapethat creates a helical passage 208 between the walls 206. Gas travellingalong the outer plenum 106, as previously described, which willeventually exit the burner through the outer nozzle opening 217, isforced to travel through the helical passages 208 and take on atangential velocity component, which induces a swirl. The swirling gasexiting the outer nozzle opening 217 allows the outer jet to expandwider and create a thicker flame shape during operation.

The present disclosure describes, therefore, in one aspect, a burner.The burner includes a casing that encloses an outer plenum formed in thecasing, and a fuel inlet opening is formed in the casing. An outernozzle opening is formed at an end of the casing. An inner tube extendsgenerally concentrically through the outer plenum, the inner tubeforming an inner plenum such that the casing encloses the outer plenumand the inner plenum, the inner plenum extending generallyconcentrically with respect to the outer plenum. An inner nozzle openingis formed at an end of the inner tube, the inner nozzle being disposedgenerally concentrically with respect to the outer nozzle. A valvearrangement is configured and operates to adjust a fluid velocityseparately through each of the outer nozzle and the inner nozzle.

In one embodiment, the burner further includes a manual activationmechanism to adjust the fluid flow velocity through each of the outerand inner nozzles by use of the valve arrangement, and in anotherembodiment the burner includes instead an automated activation mechanismto adjust the fluid flow velocity though each of the outer and innernozzles by use of the valve arrangement. In one embodiment, the burnerfurther includes a swirling device to impart swirl to fluids exitingthrough the outer nozzle.

In one embodiment, the valve arrangement includes an intermediate tubedisposed around the inner tube, a first sealed bushing extendinggenerally radially between the casing and the intermediate tube suchthat it fluidly blocks a radial gap therebetween while also permittingsealable sliding displacement between the casing and the intermediatetube, a second sealed bushing extending generally radially between theintermediate tube and the inner tube to fluid block a radial gaptherebetween while also permitting sealable sliding displacement betweenthe intermediate tube and the inner tube, a series of axially aligned,fuel inlet slots formed along the inner tube, a series of fuel passagesformed along the intermediate tube, a frusto-conical valve elementconnected at an end of the intermediate tube that is disposed within thecasing and is arranged to move with the intermediate tube in unison asthe intermediate tube slides relative to the inner tube, and a valveseat formed on a collar that is integrated with the outer tube casingwith which the frusto-conical valve is slidably associated. In this way,as the inner tube and intermediate tube are moved relative to the casingand to one another, a variable alignment between the fuel inlet slotsand the fuel passages determines a fluid flow rate through the innertube, and thus the inner nozzle, and, as the intermediate tube andfrusto-conical valve element move with respect to the valve seat, avariable flow opening is created between the frusto-conical valveelement and the valve seat, which determines a fluid flow rate throughthe outer plenum, and thus the outer nozzle.

In another aspect, the disclosure describes a burner that includes threeconcentric cylinders with tapered or thickened ends, the opposing end ofeach cylinder being blocked or otherwise plugged. Outer and innerconcentric nozzles are formed in radial gaps between the threeconcentric cylinders. Each cylinder is sealably translatable in an axialdirection relative to the remaining two concentric cylinders such that across-sectional area between the three concentric cylinders changes tocontrol a proportion of gas flow to an outer nozzle formed between anoutermost cylinder and an intermediate cylinder, and an inner nozzleformed in the innermost cylinder. An intermediate plenum is formedbetween the intermediate cylinder and the innermost cylinder is blockedor otherwise plugged at both ends. Radial holes are formed in each ofthe three cylinders, the radial holes providing the only gas conduitsbetween an outer plenum, which is defined between the outermost cylinderand the intermediate cylinder, and an inner plenum, defined within theinnermost cylinder. During operation, gas flow originating from a gasinlet formed in the outermost cylinder is fluidly provided to the innerplenum through the radial holes. The gas inlet is in fluid communicationwith a fuel source.

In one embodiment, a manual activation mechanism is used to adjust anaxial position of the intermediate cylinder and the innermost cylinderseparately with respect to the outermost cylinder, thus selectivelyaligning the radial holes in the intermediate cylinder and the innermostcylinder to control a fluid flow area therebetween, and in anotherembodiment the manual activation mechanism comprises a knob acting on athreaded rod that is threadably engaged with an activation arm that isconnected to a sealed bushing, such that motion of the knob causes arelative motion of a respective tube with respect to the outermostcylinder. In an alternative embodiment, an automated activationmechanism is used to axially, separately move the intermediate cylinderand the innermost cylinder with respect to the outermost cylinder.

In one embodiment, the outer gas nozzle includes a swirling deviceadapted to impart swirl to an outer gas jet, creating a wide flameshape. In one embodiment, the inner tube is open at both ends forming apassage adapted to provide cooling air when the burner is not operating,which passage is blocked during burner operation. In one embodiment, theradial holes in the intermediate cylinder and inner cylinder are locatedsuch that they are fluidly blocked when the intermediate cylinder isdisposed at a limit position, and wherein gas flow through the innernozzle is blocked when the intermediate cylinder is at the limitposition.

In yet another aspect, the disclosure describes a method for separatelycontrolling flow rate and/or velocity of gas provided to concentricnozzle outlets for a burner. The method includes providing a casing thatencloses an outer plenum formed in the casing, providing fuel to theouter plenum through a fuel inlet opening formed in the casing,providing an outer nozzle opening formed at an end of the casing, theouter nozzle providing the fuel to an oxidant rich environment,providing an inner tube extending generally concentrically through theouter plenum, the inner tube forming an inner plenum such that thecasing encloses the outer plenum and the inner plenum, the inner plenumextending generally concentrically with respect to the outer plenum, andproviding an inner nozzle opening formed at an end of the inner tube,the inner nozzle being disposed generally concentrically with respect tothe outer nozzle. In accordance with the method, a fuel velocityseparately through each of the outer nozzle and the inner nozzle isadjusted separately to shape a flame extending therefrom.

In one embodiment, the method further includes activating manually thefluid flow velocity through each of the outer and inner nozzles by useof a valve mechanism, and in another embodiment the method includesautomatically activating a valve mechanism to adjust the fluid flowvelocity though each of the outer and inner nozzles. In one embodiment,swirl is imparted to fuel exiting the outer nozzle. In one embodiment,the fuel velocity through each of the outer nozzle and the inner nozzleis adjusted to shape the flame by providing an intermediate tubedisposed around the inner tube, forming a series of axially aligned,fuel inlet slots along the inner tube, forming a series of fuel passagesalong the intermediate tube, providing a valve element on theintermediate tube, and providing a valve seat connected to the casingand cooperating with the valve element to adjust a flow area through theouter plenum from the fuel inlet, such that moving the inner tuberelative to the casing to variably align the fuel inlet slots and thefuel passages and determines a fluid flow rate through the inner tube,and thus the inner nozzle and moving the intermediate tube with respectto the casing to create a variable flow opening between thefrusto-conical valve element and the valve seat, which determines afluid flow rate through the outer plenum, and thus the outer nozzle.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and “at least one” andsimilar referents in the context of describing the invention (especiallyin the context of the following claims) are to be construed to coverboth the singular and the plural, unless otherwise indicated herein orclearly contradicted by context. The use of the term “at least one”followed by a list of one or more items (for example, “at least one of Aand B”) is to be construed to mean one item selected from the listeditems (A or B) or any combination of two or more of the listed items (Aand B), unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

We claim:
 1. A burner, comprising: a casing that encloses an outerplenum formed in the casing; a fuel inlet opening formed in the casing;an outer nozzle opening formed at an end of the casing; an inner tubeextending generally concentrically through the outer plenum, the innertube forming an inner plenum such that the casing encloses the outerplenum and the inner plenum, the inner plenum extending generallyconcentrically with respect to the outer plenum; an inner nozzle openingformed at an end of the inner tube, the inner nozzle being disposedgenerally concentrically with respect to the outer nozzle; and a valvearrangement configured and operating to adjust a fluid velocityseparately through each of the outer nozzle and the inner nozzle.
 2. Theburner of claim 1, further comprising a manual activation mechanism toadjust the fluid flow velocity through each of the outer and innernozzles by use of the valve arrangement.
 3. The burner of claim 1,further comprising an automated activation mechanism to adjust the fluidflow velocity though each of the outer and inner nozzles by use of thevalve arrangement.
 4. The burner of claim 1, further comprising aswirling device to impart swirl to fluids exiting through the outernozzle.
 5. The burner of claim 1, wherein the valve arrangementcomprises: an intermediate tube disposed around the inner tube; a firstsealed bushing extending generally radially between the casing and theintermediate tube such that it fluidly blocks a radial gap therebetweenwhile also permitting sealable sliding displacement between the casingand the intermediate tube; a second sealed bushing extending generallyradially between the intermediate tube and the inner tube to fluid blocka radial gap therebetween while also permitting sealable slidingdisplacement between the intermediate tube and the inner tube; a seriesof axially aligned, fuel inlet slots formed along the inner tube; aseries of fuel passages formed along the intermediate tube; afrusto-conical valve element connected at an end of the intermediatetube that is disposed within the casing and is arranged to move with theintermediate tube in unison as the intermediate tube slides relative tothe inner tube; and a valve seat formed on a collar that is integratedwith the outer tube casing with which the frusto-conical valve elementis slidably associated; wherein, as the inner tube and the intermediatetube are moved relative to the casing and to one another, a variablealignment between the fuel inlet slots and the fuel passages determinesa fluid flow rate through the inner tube, and thus the inner nozzle; andwherein, as the intermediate tube and the frusto-conical valve elementmove with respect to the valve seat, a variable flow opening is createdbetween the frusto-conical valve element and the valve seat, whichdetermines a fluid flow rate through the outer plenum, and thus theouter nozzle.
 6. A burner, comprising: three concentric cylinders withtapered or thickened ends, the opposing end being blocked or otherwiseplugged, wherein outer and inner concentric nozzles are formed in radialgaps between the three concentric cylinders, wherein each cylinder issealably translatable in an axial direction relative to the remainingtwo concentric cylinders such that a cross-sectional area between thethree concentric cylinders changes to control a proportion of gas flowto an outer nozzle formed between an outermost cylinder and anintermediate cylinder, and an inner nozzle formed in an innermostcylinder, wherein an intermediate plenum formed between the intermediatecylinder and the innermost cylinder is blocked or otherwise plugged atboth ends; and radial holes formed in each of the three cylinders, theradial holes providing the only gas conduits between an outer plenum,which is defined between the outermost cylinder and the intermediatecylinder, and an inner plenum, defined within the innermost cylinder;wherein, during operation, gas flow originating from a gas inlet formedin the outermost cylinder is fluidly provided to the inner plenumthrough the radial holes, and wherein the gas inlet is in fluidcommunication with a fuel source.
 7. The burner of claim 6, wherein amanual activation mechanism is used to adjust an axial position of theintermediate cylinder and the innermost cylinder separately with respectto the outermost cylinder, thus selectively aligning the radial holes inthe intermediate cylinder and the innermost cylinder to control a fluidflow area therebetween.
 8. The burner of claim 7, wherein the manualactivation mechanism comprises a knob acting on a threaded rod that isthreadably engaged with an activation arm that is connected to a sealedbushing, such that motion of the knob causes a relative motion of arespective tube with respect to the outermost cylinder.
 9. The burner ofclaim 6, wherein an automated activation mechanism is used to axially,separately move the intermediate cylinder and the innermost cylinderwith respect to the outermost cylinder.
 10. The burner of claim 6,wherein the outer gas nozzle includes a swirling device adapted toimpart swirl to an outer gas jet, creating a wide flame shape.
 11. Theburner of claim 6, wherein an inner cylinder is open at both endsforming a passage adapted to provide cooling air when the burner is notoperating, wherein the passage is blocked during operation of theburner.
 12. The burner of claim 6, wherein the radial holes in theintermediate cylinder and an inner cylinder are located such that theyare fluidly blocked when the intermediate cylinder is disposed at alimit position, and wherein gas flow through the inner nozzle is blockedwhen the intermediate cylinder is at the limit position.
 13. A methodfor separately controlling flow rate and/or velocity of gas provided toconcentric nozzle outlets for a burner, the method comprising: providinga casing that encloses an outer plenum formed in the casing; providingfuel to the outer plenum through a fuel inlet opening formed in thecasing; providing an outer nozzle opening formed at an end of thecasing, the outer nozzle providing the fuel to an oxidant richenvironment; providing an inner tube extending generally concentricallythrough the outer plenum, the inner tube forming an inner plenum suchthat the casing encloses the outer plenum and the inner plenum, theinner plenum extending generally concentrically with respect to theouter plenum; providing an inner nozzle opening formed at an end of theinner tube, the inner nozzle being disposed generally concentricallywith respect to the outer nozzle; and adjusting a fuel velocityseparately through each of the outer nozzle and the inner nozzle toshape a flame extending therefrom.
 14. The method of claim 13, furthercomprising activating manually the fluid flow velocity through each ofthe outer and inner nozzles by use of a valve mechanism.
 15. The methodof claim 13, further comprising automatically activating a valvemechanism to adjust the fluid flow velocity though each of the outer andinner nozzles.
 16. The method of claim 13, further comprising impartingswirl to fuel exiting the outer nozzle.
 17. The method of claim 13,wherein adjusting the fuel velocity through each of the outer nozzle andthe inner nozzle to shape the flame comprises: providing an intermediatetube disposed around the inner tube; forming a series of axiallyaligned, fuel inlet slots along the inner tube; forming a series of fuelpassages along the intermediate tube; providing a valve element on theintermediate tube; and providing a valve seat connected to the casingand cooperating with the valve element to adjust a flow area through theouter plenum from the fuel inlet; moving the inner tube relative to thecasing to variably align the fuel inlet slots and the fuel passages anddetermines a fluid flow rate through the inner tube, and thus the innernozzle; and moving the intermediate tube with respect to the casing tocreate a variable flow opening between a frusto-conical valve elementand the valve seat, which determines a fluid flow rate through the outerplenum, and thus the outer nozzle.